Tool capsule for powder compacting press



Dec, 1o, 1968 P. WNSQN 3,414,940

'Y TOOL CAPSULE FOR POWDER COMPACTING PRESS Filed April 21, 1966 2Sheets-Sheet l ATTORNEY F. VINSON TOOL CAPSULE FOR POWDER COMPACTINGPRESS Dec. 10, 1968 2 Sheets-Sheet 2 Filed April 2l, 1966 l@ Q N, Lf97%/ IV wa y- ZM@ AT TO RN EY United States Patent O 3,414,940 TOOLCAPSULE FOR PGWDER COMPACTING PRESS Paul Vinson, Costa Mesa, Calif.,assignor to Pentronix, Inc., Lansing, Mich. Filed Apr. 21, 1966, Ser.No. 544,285 2 Claims. (Cl. 18-16) ABSTRACT F THE DISCLOSURE A unitarytool capsule for mounting on a powder compacting press and having a dieplate provided with a plurality of die cavities, a housing disposedbelow the die plate and holding a plurality of hollow punches eachdisposed in one of the die cavities. The punches are collectivelyactuated by a c-ommon actuating member permitting free radial individualdisplacement of the punches, and a core rod is disposed within thelongitudinal bore of each punch. The core rods are fixedly butadjustably mounted on the end of a sleeve which is in turn adjustablybut fixedly mounted in the housing.

This invention relates to powder compacting presses and moreparticularly to an improved tool capsule assembly for such presseshaving means providing an accurate adjustment ofthe die cavitydimensions to insure a more precise dimensional control over thefinished compacted article.

The present invention is an improvement over a tool capsule of thecharacter provided as part of the powder compacting press disclosed inco-pending application Ser. No. 450,427 filed Apr. 23, 1965, nowabandoned, in continuing applications Ser. Nos. 529,733 and 529,734,filed Feb. 24, 1966, now U.S. Patents 3,328,840 and 3,344,213,respectively, in continuing application Ser. No. 529,842, filed Feb. 24,1966, now U.S. Patent No. 3,328- 842, and in continuing application Ser.No. 618,230', filed Feb. 23. 1967. The powder compacting press describedand claimed in the co-pending patent application consists of a machinefor the purpose of manufacturing cores, beads, pellets, and the likemade of powdered ferrite, glass, or other comparable powdered substancescapable of forming a product upon the application of a pressure in aconfined molding cavity. The primary purpose of the machine is themanufacture of computer memory cores which are normally toroidal, pillssuch as pharmaceuticals, balls for ball point pens, porous bearings andbushings, and the like, Computer memory cores and porous bearings, andbushings normally have a toroidal or cylindrical shape, whilepharmaceuticals may take the form of tablets such as aspirin tablets,and balls for ball point pens are formed with a spherical shape.

Small compacted articles often `require a high degree of dimensionalcontrol. For instance ferrite memory cores have dimensions ranging fromapproximately .005 to .015 inch in thickness, and from approximately.O05 to .025 inch in diameter, and the tolerance of these dimensionsnormally must be held to within one tenth of a thousandths of an inch.In addition to dimensional control, the density of compacted articles ofthis character such as memory cores must also be held accurate, therebymaking it necessary that the amount of powder placed in each die cavityof the press must be substantially the same and must be repetitivelymaintained within extremely close limits. The finished density of allthe finished cores must be the same, that is, it must be uniform andaccordingly, the compressing of the powdered material must be exact andrepeatedly constant. If these dimensional and denstiy specifications arenot held within close tol- ICC erances the play back level from thecores in a memory ban'k will not be substantially constant from core tocore. In order to realize acceptable dimensional tolerances, it isnecessary that the press be capable of accurate adjustment of themovements of several component parts within at least 15 millionths of aninch, and that precautions be taken to insure correct fill of each diecavity.

In the preferred embodiment of the powder compacting press as disclosedin the aforementioned co-pending application, the articles are compactedand formed in a multi-cavity die. The finished articles areautomatically ejected from the die, picked up by a vacuum suction headand delivered into vials or bottles. A flipper assembly, which is partof the press, is mounted movably transversely over the die plate andcarries a secondary powder hopper, an anvil, and a vacuum pick up head.The secondary powder hopper which is supplied with powder from a primaryhopper connected thereto by means of a flexible tubing, is firstpositioned over the die cavities, which are filled with powder tooverow, the punches are displaced upwardly so as to expel from the diecavities a predetermined amount of excess powder, the hopper is removedwhile wiping the die plate surface clean from excess powder and replacedby the anvil which is in turn positioned on the upper surface of the`die and over the die cavities.

The powder in each die cavity is then compacted against the anvil by theway of the punches. The anvil is removed from its position over the diecavities and replaced by the vacuum pick-up head. The punches are thendisplaced so as to bring their upper ends substantially flush with theopening of each die cavity, so that the finished compacted articles areejected from the -die cavities and picked up by the vacuum pick-up head.The vacuum pick-up head is then moved from over the die cavities anddisposed over a series of apertures arranged in a disposition similar tothe arrangement of the die cavities in the die, preferably in a circle,and the finished articles dropped through the apertures into separatevials or bottles.

In the aforementioned co-pending patent application, the preferred toolcapsule for forming an article having a toroidal shape comprised a dieplate having a plurality of equiangularly spaced bores arranged in acircle, a punch associated With each of the bores and adapted to bedisplaced in the bore to form a cavity for the powder between the headof the punch and the surface of the die plate, and a core rod associatedwith each of the punches and axially slidable in a longitudinal bore inthe punch. During the compacting cycle, the core rod would be displacedupwardly in the cavity so that its head would be flush with the surfaceof the die plate and then the powder disposed around the core rod wouldthen be compressed by the punch moving toward the anvil disposed overthe cavity. Thus the movements of both the core rods and the punch wouldhave to be precisely controlled during each cycle.

The present invention represents an improvement over the aforementionedapparatus in that each of the core rods are adjusted to be ush with theupper surface of the die plate and then it is held stationary in thisposition during the operation of the machine, `while the punches aredisplaced axially in the cavities in a regular cycle to form compactedtoroidal shaped articles. Thus the instantaneous position of only asingle movable member in the die cavity need be controlled thus insuringa more accurate dimensional control.

A major problem associated with high production automatic powdercompacting presses of this character is the maintainance of a highdegree of surface finish of the various members exposed to the powderand associated with the dimensional tolerance of the finished articles.To

insure a high degree of acceptable dimensional. tolerances, the dieplate and the punches are normally formed of a hardened tool steel ortungsten carbide and the surface of the die plate and the anvil normallyprovided with a super finish. However, some powdered substances, forinstance powdered ferrite, used in the formation of computer memorycores have highly abrasive properties. Thus the upper surface of the dieplate tends to become rounded with wear as the flipper assembly whichtraverses the die plate sweeps the excess powdered ferrite from thesurface of the die plate prior to moving the anvil into engagement overthe filled cavities. This sweeping action tends to wears the die plateso that acceptable dimensional tolerances are soon lost. In addition,the upper ends of the punches become worn due to their repeatedcompaction of the powdered ferrite. Normally the conventional toolcapsule has to be disassembled and the Working surface of the die platerefinished, and the core rods refinished or replaced depending upon theamount of Wear which has developed, and then the various componentsreassembled for further utilization.

The tool capsule illustrating the preferred embodiment of the presentinvention reduces the time and effort involved in renovating the workingsurfaces of the die plate and the core rods by providing a structure inwhich the die plate, core rods, punches, punch holder, and the relatedparts are removed as one complete assembly from the press, and all theparts relinished by turning the assembly face down on a conventionallapping disk. The configuration of the several components is such thateach of the working surfaces abut the lapping disk and aresimultaneously finished or lapped.

It is, therefore, an object of the present invention to provide atooling capsule for a powder compacting press constructed to insure morereliable and repetitive control of dimensional tolerance by reducing toa minimum the number of moving parts associated with the finished memberor article during each cycle.

It is another object of the present invention to reduce the time andeffort in renovating the working surfaces of the tool capsule in apowder compacting press by providing such a capsule in which all of theworking surfaces may be refinished without disassembling the capsule.

Still further objects and advantages of the present invention willbecome apparent to one skilled in the art upon reference to thefollowing detailed description and the accompanying drawings in whichlike reference numeral represent like parts throughout the several viewsand in which;

FIGURE 1 represents a schematic cross sectional view of a tool capsuleaccording to the present invention and including an anvil disposed overthe die cavities;

FIGURE 2 is a sectional view as seen from line 2 2 of FIGURE 1;

FIGURE 3 is an enlarged sectional View of the tooling capsule shown inthe `die cavity fill position;

FIGURE 4 is a fragmentary enlarged sectional of the tooling capsuleshown in the press position;

FIGURE 5 is a fragmentary enlarged sectional view of the tooling capsuleshown in the eject position; and

FIGURE 6 is the sectional view as seen from lines 6-6 of FIGURE 1.

Now referring to the drawings and in particular to FIGURE l, a powdercompacting press (not shown) comprises a table portion 10 having acounter bore 12 in which is seated a preferred tool housing 14. The toolhousing 14 is generally cylindrical in shape and defines an axial bore16.

A `die plate 18 preferably having a flat upper surface is disposed ontop of the housing 14 and is held to the upper surface of the table 10and to the tool housing by suitable means (not shown) such as clamps,screws or the like. The axis of the tool housing bore 16 is disposednormally to the upper surface of the die plate 18.

The die plate 18 is provided with a plurality of mutually parallel bores20 preferably disposed in a circular arrangement around the axis of thebore 16 and having a regular peripheral spacing. Associated with each ofthe bores 20 is a die bushing 22 preferably formed of a hard materialsuch as a carbide and which is press tted or otherwise fastened into thebore 20. Now as can best be seen in FIGURE 3 the die bushing 22 isinserted in the bore 20 such that its upper end is ush with the uppersurface of the die plate 18, and has a length which terminates justshort of the lower surface of the die plate.

Each of the die bushings 22 is provided with a longitudinal bore 24which extends normally inwardly from the upper face of the die plate 18and is provided with a chamfered portion 26 at the lower end thereof, asbest seen in FIGURE 3.

Now referring to FIGURE 1, an elongated cylindrical sleeve member 28 isslidably disposed Within the bore 16 of the tool housing 14. Thecylindrical sleeve member 28 has formed on its outer surafce a flattenedsurface 30 which is adapted to register with a set screw 32 carried byhousing 14. Thus it can ybe seen that the cylindrical sleeve member 28may be adjusted up and down Within the bore of the tool housing 14 andthen locked in place for a purpose which will subsequently be described.

Adjacent to the upper end of the cylindrical sleeve member 28 is anannular slot 34. A plurality of bores 36 extend longitudinally throughthe Wall of the cylindrical sleeve member 28 from the annular slot 34 toterminate at the lower end with a threaded passage 38 which accommodatesa set screw 40. The bores 36 have an identical angular and radialdisposition with respect to the axis of the sleeve member 2S as thebores 20 in the die plate have with the housing bore 16, there being onebore 36 which is associated with each of the bores 20. Thus it is to beunderstood that the bores 36 are identical with one deviation which canbest be seen in FIGURE 2. One of the bores 36 is shortened toaccommodate a set screw 42 which is radially adjustable at the lower endof the member 28 for a purpose which will be subsequently noted. It isto be understood that each of the set screws is adapted to be adjustedupwardly and downwardly by an elongated tool (not shown) which may beinserted through the opening to the threaded passage 38 provided at thelower end of the member 28.

An elongated rod member 44 is provided for each of the bores 36 and isslidably disposed therein. The rods 44 have a length sufficient suchthat their upper end extends slightly into the annular slot 34 andextend downwardly through the bore 36 such that the lower end of the rod44 will normally abut the upper end of the set screw 40. Thus there willbe in the case of an eight die tool capsule seven similarly shaped rodmembers and one short rod member to accommodate the shortened bore 36associated with the set screw 42.

A plurality of regularly spaced radial slots 46 are formed inwardly fromthe upper end of the cylindrical member 28 with one slot 46 aligned witheach of the bores 36.

Still referring to FIGURE l, an upwardly extending elongaated core rod48 is associated with each of the radial slots 46 and has an enlargedlower end 50. The lower end 50 has a length which is slightly less thanthe Width of the annular slot 34 so that the enlarged end 50 may beinserted radially into the slot with the core rod 48 registering in theradial slot 46.

The slots 46 are adapted so that each of the core rods 48 may be axiallyaligned with the die bushing bores 24. The core rods 48 have a diameterto accommodate the bore of a toroidally shaped article and have a lengthsuflicient so the upper ends thereof may be disposed flush with theupper surface of the die plate 18.

The cylindrical sleeve member 28 is provided with an axial bore 52 inwhich is slidably disposed an elongated punch holder 54. The punchholder 54 has an enlarged upper end 56 which is provided with aplurality of radial slots 58 corresponding to the die bushing bores 24as can best be seen in FIGURE 6. Thus it can be seen that each of thecore rods 48 extends upwardly through one of the radial slots 58 in theupper end of the punch holder 54. As can best be seen in FIGURE 3, anannular groove 60 is formed in the enlarged end 56 of the punch holderand carries a plurality of cylindrical members 62 each of which have anenlarged lower end 64 which is seated in the groove 60. Each of themembers 62 is provided with an axially extending elongated cylindricalpunch 66 which extends upwardly therefrom to register in a die bushing.The outer diameter of each of the punches 66 accurately fit the innerdiameter of each of the die bushings 22, and each punch has alongitudinal bore 67 having an inner diameter closely fitting the corerod 48. Each punch 66 is thus slidably guided over each core rod 48 suchthat it isfree for up and down movement.

The punch holder 54 has a at portion 68 which as can best be seen inFIGURE 2 registers with the set screw 42. Thus it can be seen that thepunch holder 54 can be locked with respect to the cylindrical member 28byrmeans of the screw 42. The lower end of the punch holder 54 isprovided with a notched portion 69 which is adapted to engage anactuating member (not shown).

Prior to installation in the compacting press, the various components ofthe preferred tool capsule are assembled with respect to one another asfollows. The cylindrical sleeve member 28 carrying the core rods 48 andthe punches 66 is hmoved upwardly in the housing 14 until the punchesare inserted into the die bushing 22 assisted by the chamfered portions26. The punches 66 are moved upwardly such that they are substantiallyself-aligned within the die bushings 22, each of the core rods 48 isthen locked to the cylindrical sleeve member 28 by the set screws 40which force the rods 44 upwardly to abut the enlarged end of the corerods and lock them between the upper end of the rods 44 and the upperinner face of the slot 34. The cylindrical sleeve member 28 is thenmoved upwardly until the upper ends of the core rods 48 are flush withthe upper surface of the die plate 18. The sleeve member 28 is thenlocked to the tool housing 14 by the adjusting set screw 32. The punches66 can now freely slide up and down the core rods 48 and within the diebushing bores 24.

The lower set screw 42 is normally engaged to lock the punch holder 54with the sleeve member 28 when the tool capsule is not assembled withthe compacting press. When the preferred tool capsule is seated in thecompacting press, the lower end of the punch holder normally is engagedwith an actuating member (not shown) and which is adapted to reciprocatethe punch holder during the various steps of the pressing cycle so thatthe locking screw 42 is disengaged.

For purposes of illustration, a typical powder compaction cycle includesa powder filling step, a compression step and an ejection step. Brieflythe filling step is diagramatically illustrated in FIGURE 3 andcomprises a powder supply device or what is commonly referred to as ahopper '70 which is disposed over the die bushing bore and which fillsthe cavity defined by the bore 24 and the upper end of the punch 66. Forthis step the punch 66 is displaced a suitable distance from the uppersurface of the die plate 18, when the cavity is filled with a powderedmaterial the punch 66 is then displaced slightly upward to expel excesspowder and to insure that the cavity space is filled with powder. Thehopper 70 is then removed by means (not shown) and the upper surface ofthe die plate wiped `clean of any excess powder which can beaccomplished by the hopper being moved transversely across the uppersurface of the die plate. The upper surface of the die plate ispreferably polished t0 'a super finish so that there is no possibilityof any grains of powder remaining on this surface after the wiping step.

Referring to FIGURES 1 and 4, an anvil 72 supported by anvil holder 74is transferred over the filled die cavity and the punch holder 54actuated to force the punches 66 upwardly such as to compress the powdercontained in the cavities against the anvil to form the compacted finished articles. The anvil is then removed from over the die cavities andthe punches 66 preferably displaced upwardly so that their ends aresubstantially liush with the upper surface of the die plate 18 so thatthey eject the finished articles which may be picked up by any suitablemeans and preferably deposited in .a plurality of passages 76, one ofwhich is shown in FIGURE 1.'Each passage 76 delivers the finishedarticle through a conduit 78 which discharges the finished article to avial or bottle (not shown).

Because of the highly abrasive properties of some of the powderedsubstances utilized in presses of this character the upper surface ofthe die plate 18 and the upper end of the core rods 48 tend to becomerounded and worn. The wearing surfaces of the preferred tool capsule canbe renovated by removing the capsule from the compacting press andinverting it so that the die plate 18 abuts a conventional lapping tool.lBy disengaging the set screw 32, the core rods 48`and the punches 66are free to move downwardly to abut the lapping tool so that all of theworn surfaces are simultaneously ground to the desired finish. Thus itcan be seen that the improved tool capsule can be renovated withoutdisassembling the various parts. Furthermore, it can be seen that a moreprecise dimensional control of the finished articles can be maintainedin the improved tool capsule because of the fewer number of moving partswhose relative movements have to be controlled.

It can also be seen that the construction of the tool capsule of thepresent invention provides for assembling the core rods and the punchesin an appropriate housing in such manner that the core rods areindividually precisely positioned longitudinally relatively to thesleeve holding all the core rods, while the sleeve is in turn preciselypositioned longitudinally relatively to the housing. The punches areactuated in unison lby means of a common actuating member, and thepunches and core rods, although accurately located along a longitudinalaxis, are substantialy free to lioat radially such as to permit thepunches to align themselves within the die bushings.

Although I have described only one preferred embodi ment of my inventionit `will be apparent to anyone skilled in the art to which the inventionpertains that various changes and modifications may ybe made thereinwithout departing from the spirit of the invention as expressed in thescope of the appended claims.

I claim:

1. A unitary tool capsule for making articles compacted of powder, saidtool capsule comprising:

a die plate adapted to be mounted in an appropriate aperture ina machinebase;

said die plate having a plurality of substantially circularly arrangeddie cavities, each of said die cavities being shaped as a rightcylindrical :bore open on both ends;

a housing mounted below said die plate;

a plurality of punches in said housing each having an end engaged in oneend of each of said die cavities and reciprocable therewithin, each ofsaid punches snugly fitting within each of said die cavities;

an enlarged portion on the other end of each of said lpunchesoperatively connected to a punch actuating mem-ber having .a pluralityof radial slots each affording passage to the body of each of saidpunches and a peripheral groove defining a recess adapted to receivesnugly a plurality of said enlarged portions, wherein each of saidpunches is free to radially 7 8 float relatively to said punch actuatingmember for adjusting means for said sleeve member tolongitudiself-centering relatively to each of said cavities and nallyadjust the position of said sleeve member relais positivelylongitudinally reciprocated by said punch tively to said housing.actuating member with substantially no back lash; 2. The unitary toolcapsule of claim 1 ifurther comprisa longitudinal bore extending fromend to end in each 5 ing means fOT IOCking Said Punch actuating memberrelaof said punches; tively to said sleeve member. a plurality of corerod members each slidably and snugly disposed within said longitudinalbore and References Cled having .arfi eni projcting through the enlargedend UNITED STATES PATENTS portiono sai punc an enlarged portion on saidprojecting end of each of 10 gogt 'al gg said core rod members forconnection to an end of 2338491 H1944 Cutler 18 l16 5 a Sleeve memberslidably disposed in said housing 2640125 6/1953 Hauer "18 16 5 andhaving a plurality of radial slots afording pas- 286744 1/1959 Hau B 'M5 Sage t0 the body 0f each of said core rod member 15 3060506 10/1962UschH-lgxul 18-16'5 and a peripheral ygroove defining a recess adaptedto 3132379 5/1964 Crane 18 16's receive snugly a plurality of saidenlarged portions 3328840 7/1967 Vinson l? 6 for holding of said corerod members independently 3328842 .H1967 Vinson 18 T6 5 0f Said punches,wherein each of said core rod mem- 2272116 1/1966 Fessel "18 36 bers isfree to radially oat relatively to said rod 20 member holding member forself-centering relative- 1 HOWARD FLINT JR. Primary Examine'.

1y to each of said punch longitudinal bores; individual .adjusting meansfor each of said core rod Us. Cl- X-R- members to longitudin-ally adjustthe position of 18-16-5 each of said core rod members relatively to said25 sleeve member; and

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,414,940 December 10, 1968 Paul Vinson It is certified that error appears inthe above identified patent and that said Letters Patent are herebycorrected as shown below:

In the heading to the printed specification, lines 4 and 5, "Pentronix,Inc. Lansing, Michigan" should read Pentronx, Inc. a corporation ofMichigan Signed and sealed this 10th day of March 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, J r.

Attesting Officer

